Montie Eric W.

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Eric W.

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  • Technical Report
    Imaging procedures for stranded marine mammals
    (Woods Hole Oceanographic Institution, 2008-01) Ketten, Darlene R. ; Montie, Eric W.
    This section provides an introduction to biomedical imaging techniques and guidelines for diagnostic imaging of marine mammals to assist with both live examination and necropsy procedures. The procedures described are based on imaging equipment and techniques that are relatively common in human and veterinary facilities and to provide the majority of stranding response groups with the most likely options that will assist their efforts. The imaging techniques described include basic radiography, computed tomography (CT), and magnetic resonance imaging (MRI) and are applicable to both live and post-mortem cases. Special emphasis has been placed on whole body, airway, head and ear imaging procedures. Sub-sections cover basic information on the basic principles and appropriate applications for radiography vs. CT vs. MRI, handling and preparation of live and dead animals in clinical settings, and image and data formats that may be encountered. The protocols are also listed in outline form in order to provide a rapid overview. The introductory discussion of principles behind techniques is not required to employ the protocols but does provide additional information that can aid in deciding which techniques are most efficacious and what the limitations are for interpretation of imaging data. Examples of some pathology imaged with these procedures are also provided.
  • Preprint
    Organohalogen contaminants and metabolites in cerebrospinal fluid and cerebellum gray matter in short-beaked common dolphins and Atlantic white-sided dolphins from the western North Atlantic
    ( 2009-03-12) Montie, Eric W. ; Reddy, Christopher M. ; Gebbink, Wouter A. ; Touhey, Kathleen M. ; Hahn, Mark E. ; Letcher, Robert J.
    Concentrations of several congeners and classes of organohalogen contaminants (OHCs) and/or their metabolites, namely organochlorine pesticides (OCs), polychlorinated biphenyls (PCBs), hydroxylated-PCBs (OH-PCBs), methylsulfonyl-PCBs (MeSO2-PCBs), polybrominated diphenyl ether (PBDE) flame retardants, and OH-PBDEs, were measured in cerebrospinal fluid (CSF) of short-beaked common dolphins (n = 2), Atlantic white-sided dolphins (n = 8), and gray seal (n = 1) from the western North Atlantic. In three Atlantic white-sided dolphins, cerebellum gray matter (GM) was also analyzed. The levels of OCs, PCBs, MeSO2-PCBs, PBDEs, and OH-PBDEs in cerebellum GM were higher than the concentrations in CSF. 4-OH-2,3,3’,4’,5-pentachlorobiphenyl (4-OH-CB107) was the only detectable OH-PCB congener present in CSF. The sum (Σ) OH-PCBs/ Σ PCB concentration ratio in CSF was approximately two to three orders of magnitude greater than the ratio in cerebellum GM for dolphins.
  • Thesis
    Approaches for assessing the presence and impact of thyroid hormone disrupting chemicals in delphinid cetaceans
    (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2006-09) Montie, Eric W.
    Cetacean blubber is a primary site for lipid storage, which the animal utilizes during periods of energetic stress. It is important to understand how the blubber responds to factors such as ontogeny, water temperature, reproductive status, and nutritional state because blubber is also the primary bioaccumulation site for persistent organic pollutants (POPs) such as polychlorinated biphenyls (PCBs). During periods of lipid mobilization such as lactation, PCBs from the blubber are mobilized into the circulatory system and may cause toxic effects. One particular toxic mechanism may include the induction of cytochrome P450 enzymes in the integument and liver, which could enhance the biotransformation of PCBs to hydroxylated metabolites (OH-PCBs). OH-PCBs may then interfere with thyroid hormone dependent neurodevelopment. The goals of these studies were to investigate the relationships between lipid dynamics and PCB effects and to devise a quantitative approach to assess neurodevelopment in delphinid cetaceans. Blubber morphology, cytochrome P450 1A1 (CYP1A1) expression in the skin-blubber biopsy, blubber and plasma PCBs, and plasma OH-PCBs were assessed in bottlenose dolphins (Tursiops truncatus). In addition, magnetic resonance (MR) images of the postmortem brain in situ were obtained from Atlantic white-sided dolphin (Lagenorhynchus acutus) specimens.These results showed that: 1) Factors such as ontogeny, water temperature, and reproductive status affected blubber morphology in bottlenose dolphins. In response to warmer water, the lipid content of the blubber decreased and this appeared to involve loss of lipids from adipocytes in the middle blubber layer. Similar to the effects of starvation on blubber morphology, lactation decreased adipocyte size predominantly in the deeper blubber, 2) CYP1A1 levels in the deep blubber were significantly related to the total plasma TEQ98 concentrations, adipocyte shrinkage, and plasma OH-PCB levels, 3) Through in situ MR imaging of stranded, Atlantic white-sided dolphin specimens, the size of brain structures that depend on thyroid hormones for maturation could be measured accurately. Future studies can use this technique, coupled with chemical analysis of brain regions, to determine if thyroid hormone disrupting chemicals in delphinid cetaceans are associated with changes in the size of brain structures.